The present invention relates to a needle for a tufting machine, namely a needle comprising a shank having an eye at one end, and a mounting portion at the opposite end with a yarn guide groove extending from the eye towards the mounting portion.
One problem with needles of this type is that the top of the yarn feed or guide groove opens into the side of the needle body so that the yarn is fed into the groove at an angle. Thus, friction between the yarn and the backing material causes an increase in yarn tension which results in problems such as stretching of the backing material, unevenness in the pile height, an increased power requirement to achieve needle penetration and an increase in loose fibers. Additionally, the yarn may be damaged because it is not lying correctly or completely in the yarn groove and may be crushed between the needle body and the backing material when the needle pierces the backing.
In an attempt to overcome these problems, a thread-feeding element has been proposed in European patent application EP-A-0882831. This thread-feeding element is essentially a guide which ensures that the yarn enters the top of the yarn feed groove and is then fed directly down the length of the needle thereby greatly reducing the contact between the yarn and backing material.
However, for various reasons, the only example which has proved practical is the double-eyed cranked needle shown in FIG. 4 of EP-A-0882831. Even with this design, there are a number of disadvantages that have limited the applications of this needle. The complex structure of the needle makes it expensive to produce. The presence of the eye towards the upper end of the needle weakens the needle. The crank configuration limits the pitch (gauge) on in-line needle bars and modules. As the double-eyed configuration makes the needle difficult to thread, single staggered needle bars and modules are not practical. Thus, the needle has been used in only a limited number of applications.
A similar arrangement proposed by the applicant, as illustrated in U.S. patent application Ser. No. 09/267,488 filed Mar. 1, 1999, U.S. Pat. No. 6,152,055 has a needle which is cranked in such a way as to provide direct access to the top of the yarn feed groove. However, this also suffers from high manufacturing costs and reduced stability at the 90xc2x0 bend and may not be suitable for dual sliding needle bar machines due to threading difficulties.
Consequently, it is a primary object of the present invention to provide a needle for use in tufting machines which has an element which permits yarn to be directed readily into the yarn groove with a minimum angular deviation in its path.
It is another object of the present invention to provide a needle module mounting a plurality of needles wherein there is a common element which permits yarn to be threaded to the respective needles permitting the yarn to be directed readily into the respective yarn groove with a minimum angular deviation in each respective path.
According to the present invention, a needle of the kind described is characterized by a rod attached at the shank above the blade or in the top of the groove at the top of the blade opposite the end of the needle having the point and projecting laterally from the needle.
This simple idea has a number of very important advantages. It is inexpensive to produce as it requires only that a rod be attached to an existing type of needle. The invention can be applied to any existing arrangement of needles. As it does not require a crank type configuration, it does not limit the pitch of the needles. The presence of the rod does not weaken the needle as does the presence of a second eye.
The rod may simply be welded to the needle in or adjacent the groove in the needle. However, the current preference is for a through-hole to be provided in the needle, through which hole the rod extends. In this case, the rod is preferably retained in the through-hole by being bent at at least one location.
The needle may be individually mounted directly to a needle bar, or to a module which is fixed to the needle bar. In either case, the invention may extend to a needle assembly provided with a plurality of needles in which the rod is common to all of the needles. In this case, a yarn entrance guide will be formed by the needle, the adjacent needle, the rod, and the component to which the needles are mounted. This is a large area and provides for simple threading of the needle.
The rod is preferably chamfered at one end in order to facilitate insertion through the through-holes and to aid the insertion and extraction of a module from its backing bar without disturbing neighboring modules.